KR102328169B1 - Magnet chuck - Google Patents

Abstract

The magnet chuck 10 includes a piston 58 that is displaced in the second sliding hole 38 of the cylinder tube 14 . When the piston 58 reaches one displacement end point, one end face of the piston 58 abuts against the plate member 42, whereas when the piston 58 reaches the other displacement end point, the other end face of the piston 58 is the head cover. Abuts against the entry portion 44 of (18). At least one, preferably both, of the first damper 84 on the one end surface and the second damper 94 on the other end surface is provided on the plate member 42 .

Description

Magnet chuck {MAGNET CHUCK}

The present invention relates to a magnet chuck that attracts and holds a workpiece by the magnetic force of a permanent magnet.

The magnet chuck includes either an electromagnet or a permanent magnet. In the case of an electromagnet, a magnetic force is generated by the start of energization to the electromagnet (that is, excitation), thereby attracting and holding the work. Moreover, when electricity supply is stopped, the magnetic force is lost, and as a result, the work is released.

On the other hand, in the case of a permanent magnet, as described in, for example, Japanese Unexamined Patent Application Laid-Open No. 55-078505, there is a device for switching the release as well as the attraction and holding of the work by rotating the permanent magnet. However, in general, it is known to connect a permanent magnet to a piston and to displace the permanent magnet together with the piston (for example, refer to Japanese Utility Model Laid-Open No. 51-102174). In a magnet chuck as described in Japanese Utility Model Laid-Open No. 51-102174, the work is attracted and held as the permanent magnet approaches the work in response to the displacement of the piston subjected to fluid pressure. Further, when the permanent magnet and the piston are displaced in a direction away from the work, the work is released.

This type of magnet chuck is installed, for example, on the tip arm of the robot, and as the robot performs a predetermined operation, the suctioned and held workpiece is conveyed to a predetermined position.

When the piston and the permanent magnet are integrally displaced together, it is conceivable that, for example, the piston can abut against the head cover when the top dead center is reached. In this case, the magnet chuck vibrates and becomes one factor in generating an unpleasant sound. Moreover, there exists a possibility that the durability of a piston may fall by contact|abutting.

A main object of the present invention is to provide a magnet chuck in which vibration is suppressed when the piston reaches the displacement end point.

Another object of the present invention is to provide a magnet chuck capable of ensuring durability of a piston or the like.

According to an embodiment of the present invention, in the magnet chuck for attracting and holding a workpiece by the magnetic force of a permanent magnet, it is attached to a cylinder tube having a sliding hole through which a piston is displaced and the cylinder tube to close one end of the sliding hole a housing including a head cover; a holding member connected to the piston and holding the permanent magnet; and a partition member positioned and fixed in the housing to form an inner chamber in the cylinder tube together with the piston. The magnet chuck includes at least one of a first damper and a second damper, and the first damper is installed on either the partition member or the piston to relieve vibration when the piston comes into contact with the partition member. and the second damper is installed on either the piston or the head cover to reduce vibration when the piston comes into contact with the head cover.

In the configuration in which the first damper is provided, the first damper is interposed between the piston and the partition member when the piston reaches one of the displacement end points (for example, bottom dead center). For this reason, the vibration and shock at the time of the piston contact|abutting against a partition member are relieve|moderated. On the other hand, in the configuration in which the second damper is provided, when the piston reaches the other displacement end point (eg, top dead center), the second damper is interposed between the piston and the head cover. For this reason, the vibration and shock when a piston contacts a head cover are relieve|moderated. From the above reasons, it is avoided that the piston vibrates when the displacement end point is reached and an unpleasant sound is generated. Therefore, it is most preferable to provide both the first damper and the second damper.

Furthermore, damage to the piston, partition member, and head cover is avoided. That is, the durability of these members is ensured. Accordingly, it is possible to prolong the life of the magnet chuck.

The piston and the holding member may be connected through a shaft having a smaller diameter than that of the piston. In this case, the partition member is positioned and fixed between the piston and the holding member. Then, an insertion hole for passing the shaft is formed in the partition member. According to the above configuration, the permanent magnet can be displaced by following the piston despite the partition member being provided between the piston and the holding member.

In this case, it is preferable that the holding member and the shaft are integrally formed together by the same member. Accordingly, the number of parts is reduced.

The member having the holding member may be constituted by a yoke. In this case, the attraction force of the permanent magnet becomes stronger due to the presence of the yoke. Therefore, it becomes possible to more effectively attract and hold the work.

Further, it is preferable to configure the permanent magnet so that one or more pairs of N poles and S poles are present on the magnetically attaching surface of the workpiece facing the workpiece. In particular, it is preferable to arrange so that different magnetic poles are adjacent to each other.

In this configuration, the magnetic flux starting from the N pole exposed on the magnetic attachment surface of the work is directed to the two S poles adjacent to the magnetic attachment surface of the work. For this reason, the magnetic path (magnetic flux amount) in the workpiece increases compared to the conventional magnet chuck in which the magnetic pole of the magnetic pole of the workpiece has either the N pole or the S pole, that is, one pole. As a result, a large attractive force is expressed with respect to the work. Therefore, even when the workpiece is a thin steel sheet, the workpiece can be effectively magnetically attached.

In other words, when adopting this configuration, if the material, characteristics, etc. of the permanent magnet are the same as those of the permanent magnet of the magnet chuck according to the prior art, the attraction force to the workpiece can be increased when the dimensions are the same. On the other hand, when the attraction force is equal to that of the permanent magnet of the magnet chuck according to the prior art, the size of the permanent magnet can be reduced, so that the size (compact) of the magnet chuck can be achieved.

Furthermore, it is also considered that when the permanent magnet rotates, the magnetic flux density changes in the vicinity of the auto switch, and as a result, the auto switch may malfunction. Therefore, it is preferable to provide a rotation preventing member for preventing the permanent magnet from rotating by the connecting member connecting the cylinder tube and the head cover. This is because it is possible to dispel the fear that the above situation may be caused. In this case, the connecting member may be made of a ferromagnetic metal.

Furthermore, in this case, since the connecting member for assembling the magnet chuck functions as the rotation preventing member, there is no need to use the rotation preventing member separately from the connecting member. Therefore, since it is possible to avoid an increase in the number of parts, the size of the magnet chuck can be made more compact. Also, such a configuration is cost-effective.

When providing the connecting member as the rotation preventing member, it is preferable to arrange the connecting member at the boundary between the N pole and the S pole adjacent to each other on the work magnetic attachment surface. In this arrangement, the permanent magnet becomes the most difficult to rotate as compared with the case where the rotation preventing member is arranged at another position.

Further, it is preferable to provide a sealing member on the side wall of the piston, and to seal between the piston and the cylinder tube by the sealing member. In this case, the piston receives a pressing force from the compressed fluid in either case when the permanent magnet moves forward or retreats. The pressure-receiving area of the piston when the permanent magnet moves forward and the pressure-receiving area of the piston when it retracts are approximately equal, and therefore the driving force at the time of forward and backward is substantially equal. Accordingly, for example, it is possible to substantially equalize the response speed when the workpiece is magnetically attached and when the workpiece is released.

The above and still further objects, features and advantages of the present invention will become more apparent from the description that follows, when reference is made to the accompanying drawings in which a preferred embodiment of the present invention is shown by way of exemplary embodiment.

According to the present invention, a first damper is installed in any one of a piston displacing the cylinder tube or a partition member positioned and fixed in the cylinder tube, or any one of the piston or a head cover connected to the cylinder tube A second damper is installed on the Of course, both the first damper and the second damper may be provided.

When the first damper is provided, when the piston reaches the bottom dead center, the first damper is interposed between the piston and the partition member. On the other hand, when the second damper is provided, when the piston reaches top dead center, the second damper is interposed between the piston and the head cover. For this reason, the vibration or shock when a piston abuts against a partition member or a piston when abutting a head cover is relieved. Therefore, the possibility that vibration or an unpleasant sound may be generated is prevented.

In addition, since damage to the piston or the partition member and the head cover can be avoided, the durability of the magnet chuck is improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a principal part schematic perspective view of the magnet chuck which concerns on embodiment of this invention.
FIG. 2 is a plan view viewed from the arrow A direction in FIG. 1 .
FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 .
4 is a schematic longitudinal sectional view showing a state in which the piston, the yoke, and the first to fourth permanent magnets are displaced downward from the state shown in FIG. 3 .
5A and 5B are schematic side views of magnetic flux when the number of poles on the workpiece magnetic attachment surface is one, and plan schematic views showing magnetic saturation regions, respectively.
6A and 6B are schematic side views of magnetic flux when the number of poles on the workpiece magnetic attachment surface is two (the number of combinations of N poles and S poles is one pair), respectively, and plan schematic diagrams showing magnetic saturation regions.
Fig. 7 is a schematic plan view showing a magnetic saturation region when the number of poles on the work magnetic attachment surface is 4 (the number of combinations of N poles and S poles is 2 pairs).
Fig. 8 is a graph showing the relationship between the number of magnetic poles (the number of combinations of N poles and S poles) and the generated attraction force on the magnetically attaching surface of the workpiece.
Fig. 9 is a schematic perspective view showing a state in which a work magnetic attachment surface is formed by combining three U-shaped permanent magnets.
Fig. 10 is a schematic bottom view showing a state in which a work magnetic attachment surface is formed by combining two U-shaped permanent magnets.
Fig. 11 is a schematic front view showing a state in which a combination of a pair of N poles and S poles is provided on a magnetically attaching surface of a work by forming a Halbach arrangement with a bar magnet.
Fig. 12 is a schematic overall perspective view of a permanent magnet obtained by magnetizing a cylindrical body so that the direction of the magnetic pole is U-shaped.
Fig. 13 is a schematic overall perspective view of a permanent magnet obtained by magnetizing a cylindrical body so that the magnetic poles are directed in a direction orthogonal to the workpiece magnetic attachment surface.

EMBODIMENT OF THE INVENTION Hereinafter, the magnet chuck which concerns on this invention WHEREIN: It demonstrates in detail with reference to attached drawing, giving a suitable embodiment. In the following description, "above" and "below" correspond to above and below in FIGS. 1, 3, and 4 . In addition, in this embodiment, the case where compressed air is used as a working fluid is illustrated.

1 to 3 are a schematic perspective view of a main part of the magnet chuck 10 according to the present embodiment, a plan view viewed from the direction of arrow A in FIG. 1 , and a cross-sectional view taken along the line III-III in FIG. 2 , respectively. The magnet chuck 10 attracts and holds the work 12 shown in FIG. 3 . Of course, the work 12 is made of a ferromagnetic material, and a specific example thereof is a thin steel sheet. The thickness T1 of the work 12 is, for example, about 0.5 to 2 mm, and typically about 0.6 mm.

The magnet chuck 10 includes a housing 20 constructed by attaching a magnet cover 16 and a head cover 18 to a cylinder tube 14 . Hereinafter, referring mainly to FIG. 3 , first, the magnet cover 16 is made of a hollow body in which the first sliding hole 22 extends along the longitudinal direction thereof. The first sliding hole 22 is formed by a flange 66 (holding member) and a plate member 42 (partition member) of a yoke 64 described later, a lower chamber 23 and a first intermediate chamber 24 . is partitioned by That is, the lower chamber 23 is a space between the bottom wall portion of the magnet cover 16 and the lower end surface of the flange 66 . Further, the first intermediate chamber 24 is between the upper end surface of the flange 66 and the lower end surface of the plate member 42 .

A hollow cylindrical portion 25 is protruded from the lower end surface of the magnet cover 16, and the hollow cylindrical portion 25 has a first sliding hole 22 (lower chamber 23) at a position surrounding the first sliding hole 22 (lower chamber 23). An annular groove 26 is formed. A portion of the rubber buffer member 28 having a substantially ring shape is press-fitted into the first annular groove 26 , while the rest of the rubber buffer member 28 protrudes from the magnet cover 16 in a ring shape. A plurality of slits 29 (see FIG. 2 ) are formed in the rubber buffer member 28 .

The middle side portion 30 (see FIG. 3 ) of the magnet cover 16 is formed in a substantially rectangular parallelepiped shape, and the upper end portion 32 thereof is formed in a substantially cylindrical shape. Based on such a different shape, a step portion 34 is formed in the magnet cover 16 by the middle side portion 30 and the upper end portion 32 . A first sealing member 36 is installed on the side wall of the upper end portion 32 .

In addition, a first port 37 is formed on one side of the intermediate side portion 30 . The first port 37 communicates with the lower chamber 23 .

The cylinder tube 14 is formed with a second sliding hole 38 extending along its longitudinal direction. A cross section of the second sliding hole 38 in a direction perpendicular to the longitudinal direction has a substantially perfectly circular shape. Further, the second sliding hole 38 is opened at the lower end and upper end of the cylinder tube 14 . That is, the cylinder tube 14 is a hollow body in which the outer shape is formed in a substantially rectangular parallelepiped shape.

In the vicinity of the lower end opening of the second sliding hole 38, a thin-walled portion 40 is formed by the inner wall being depressed toward the outer wall side. For this reason, the thickness of the thin wall part 40 is set small compared with the other part. The lower end of the thin wall portion 40 abuts against the step portion 34 of the magnet cover 16 . In addition, the upper end 32 of the magnet cover 16 is fitted into the thin wall portion 40 while being inserted into the second sliding hole 38 . A space between the thin wall portion 40 and the upper end portion 32 of the magnet cover 16 is sealed by the first sealing member 36 .

An outer edge portion of the plate member 42 is interposed between the top surface of the magnet cover 16 and the ceiling surface of the thin wall portion 40 . In other words, the plate member 42 is sandwiched between the magnet cover 16 and the cylinder tube 14 . In addition, the plate member 42 is mentioned later.

The upper end opening of the cylinder tube 14 is closed by the head cover 18 . On the lower end surface of the head cover 18, a substantially cylindrical entry portion 44 is formed to protrude. As this entry portion 44 enters the cylinder tube 14 , the head cover 18 is fitted to the cylinder tube 14 . A second sealing member 46 is provided on the side wall of the entry portion 44 , and a space between the cylinder tube 14 and the head cover 18 is sealed by the second sealing member 46 .

A second port 50 is formed on one side of the head cover 18 . The second port 50 is located on the same side as the side on which the first port 37 is formed. A supply/exhaust mechanism (not shown) is connected to the first port 37 and the second port 50 .

At the four corners of the housing 20, there are bottomed rod holes 52 from the head cover 18 through the cylinder tube 14 to near the lower end of the middle side portion 30 of the magnet cover 16. ) are formed respectively. The threaded portions of the first to fourth tie rods 54a to 54d (connecting members) inserted into the respective rod holes 52 are screwed to the threaded portions formed near the bottom of the rod hole 52 . . Further, the head is stopped at an annular step 55 provided on the head cover 18 . As the first to fourth tie rods 54a to 54d are screwed together, the head cover 18 , the cylinder tube 14 and the magnet cover 16 are fastened and connected together to form the housing 20 .

In the above configuration, the head cover 18, the cylinder tube 14, and the magnet cover 16 are made of, for example, a paramagnetic metal such as an aluminum alloy. On the other hand, the first to fourth tie rods 54a to 54d are made of a ferromagnetic metal such as cast iron (for example, a material equivalent to SS400 prescribed by Japanese Industrial Standards), and as will be described later, suction holding means The phosphorus first to fourth permanent magnets 56a to 56d function as a rotation preventing member preventing rotation, that is, a so-called rotation stop.

In the housing 20 , the first sliding hole 22 and the second sliding hole 38 are partitioned by a plate member 42 . Further, the second sliding hole 38 is divided into a second intermediate chamber 60 and an upper chamber 62 by the piston 58 and the head cover 18 .

On the other hand, the upper chamber 62 is formed between the piston 58 and the entry portion 44 of the head cover 18 . The second port 50 communicates with the upper chamber 62 .

The magnet chuck 10 includes first to fourth permanent magnets 56a to 56d for attracting and holding the work 12 (see FIG. 3 ). Each of the first to fourth permanent magnets 56a to 56d is held by the yoke 64 through, for example, its own magnetic force or a connecting member such as a retaining bolt.

As shown in FIG. 2 , the first to fourth permanent magnets 56a to 56d substantially form a sector having a central angle of substantially 90° in plan view, respectively. By disposing the cylindrical body of such a shape in a circular shape, a permanent magnet of a cylindrical shape is constituted as a whole. That is, the first permanent magnet 56a contacts the second permanent magnet 56b and the fourth permanent magnet 56d adjacent to the first permanent magnet 56a, and faces the third permanent magnet 56c. do.

The radius of the first to fourth permanent magnets 56a to 56d may be set, for example, to about 10 to 30 mm. A typical example of a radius is about 15 mm, with the permanent magnet having an overall diameter of about 30 mm.

Further, a typical example of the height (distance from the lower end surface to the upper end surface) of the first to fourth permanent magnets 56a to 56d is about 10 mm.

In addition, in FIG. 2, the bottom wall part of the magnet cover 16 is not shown in order to make understanding easy. However, in reality, the first to fourth permanent magnets 56a to 56d are covered by the bottom wall portion of the magnet cover 16 (see Fig. 3).

When the first to fourth permanent magnets 56a to 56d are displaced so as to approach the work 12 integrally with the yoke 64 and the piston 58, the work 12 shown in FIG. 3 can be attracted. That is, in the first to fourth permanent magnets 56a to 56d, the surface opposite to the workpiece 12 functions as a workpiece magnetic attachment surface (surface to attract and hold).

The magnetic poles of the workpiece magnetic attachment surfaces of the first permanent magnet 56a and the third permanent magnet 56c are both N poles. On the other hand, the magnetic poles of the workpiece magnetic attachment surfaces of the second permanent magnet 56b and the fourth permanent magnet 56d are both S poles. Accordingly, the magnetic poles of the magnetic attachment surface of the workpiece are N pole (first permanent magnet 56a), S pole (second permanent magnet 56b), N pole (third permanent magnet 56c), S in the clockwise direction. poles (fourth permanent magnet 56d). That is, in this case, the combination of the N pole and the S pole is formed in two pairs on the work magnetic attachment surface, and the magnetic pole surface is exposed so that the N pole and the S pole, which are different magnetic poles, are adjacent to each other.

In addition, on the side to be held by the yoke 64, opposite to the above, clockwise S pole (first permanent magnet 56a), N pole (second permanent magnet 56b), S pole ( The third permanent magnet 56c) and the N pole (the fourth permanent magnet 56d) are arranged in this order.

The outer peripheral side of the boundary between the first permanent magnet 56a and the second permanent magnet 56b, that is, the N pole (the first permanent magnet 56a) and the S pole (the second permanent magnet) on the workpiece magnetic attachment surface. The first tie rod 54a is positioned on the outer peripheral side of the boundary with the magnet 56b). Similarly, the outer peripheral side of the boundary between the second permanent magnet 56b and the third permanent magnet 56c, the outer peripheral side of the boundary between the third permanent magnet 56c and the fourth permanent magnet 56d, and the fourth permanent magnet A second tie rod 54b, a third tie rod 54c, and a fourth tie rod 54d are located on the outer peripheral side of the boundary between the 56d and the first permanent magnet 56a, respectively. As a result, the first to fourth tie rods 54a to 54d are arranged at the boundary between the magnetic poles adjacent to the workpiece magnetic attachment surface.

Since the first to fourth tie rods 54a to 54d are made of ferromagnetic metal, the magnetic force of the first to fourth permanent magnets 56a to 56d also extends to the first to fourth tie rods 54a to 54d. . That is, an attraction force is generated between the first to fourth permanent magnets 56a to 56d and the first to fourth tie rods 54a to 54d.

Since the above-described attraction interaction occurs between the first to fourth permanent magnets 56a to 56d and the first to fourth tie rods 54a to 54d, the first to fourth permanent magnets 56a to 56d ) is prevented from rotating. Consequently, the first to fourth permanent magnets 56a to 56d function to stop the rotation of the piston 58 and the yoke 64 . In this way, the rotation torque of the first to fourth permanent magnets 56a to 56d can be substantially zero by the first to fourth tie rods 54a to 54d for forming the housing 20 .

When the first to fourth tie rods 54a to 54d are positioned as described above, the rotational torque generated in the first to fourth permanent magnets 56a to 56d is reduced to a minimum. That is, stopping the rotation can be performed more effectively.

As described above, the first to fourth permanent magnets 56a to 56d are held in the yoke 64 (see Fig. 3). That is, the yoke 64 includes a large diameter flange 66 and a small diameter shaft 68 . The first to fourth permanent magnets 56a to 56d are held by their own magnetic force at the flange 66 or by a connecting member such as a bolt. The flange 66 and the shaft 68 are integrally formed with the yoke 64 (by the same member). Further, since the yoke 64 is made of a ferromagnetic metal such as cast iron (eg, material equivalent to SS400), the first to fourth permanent magnets 56a to 56d are magnetically attached to the flange 66 . can be attached.

The thickness of the flange 66 can be set, for example, to about 10 mm. The flange 66 functions as a backup yoke. In addition, a wear ring 70 is provided on the side wall of the flange 66 . The wear ring 70 avoids causing the center of the flange 66 to shift with respect to the center of the first sliding hole 22 , and the flange 66 and by extension the yoke 64 are connected to the first sliding hole (22) Guided along the interior.

On the other hand, on the upper end surface of the flange 66, an annular concave portion 72 recessed toward the lower end surface side is formed. Further, in the upper end of the shaft 68, a bolt hole 76 for screwing the connecting bolt 74 is formed.

The plate member 42 is arranged between the first to fourth permanent magnets 56a to 56d (the flange 66 of the yoke 64 ) and the piston 58 . For this reason, an insertion hole 78 for penetrating the shaft 68 of the yoke 64 is formed through a substantially central portion of the plate member 42 . It goes without saying that the inner diameter of the insertion hole 78 is smaller than the outer diameter of the piston 58 .

Further, on the lower end surface of the plate member 42 , a disk-shaped projection 80 is formed to protrude toward the flange 66 . When the piston 58, the yoke 64, and the first to fourth permanent magnets 56a to 56d are located at top dead center, which is the displacement end point (see FIG. 3), the disk-shaped protrusion 80 is the yoke 64. It enters the annular recess 72 formed in the flange 66 .

A second wide annular groove 82 is formed on the upper end surface of the plate member 42 , and the ring-shaped first damper 84 is accommodated in the second annular groove 82 . The lower end surface of the piston 58 that has reached the bottom dead center, which is the displacement end point, abuts against the first damper 84 (see FIG. 4 ).

Furthermore, in the plate member 42, in the vicinity of the insertion hole 78, a communication groove 85 for communicating the first intermediate chamber 24 and the second intermediate chamber 60 is formed. Through this communication groove (85), the compressed air in the first intermediate chamber (24) moves to the second intermediate chamber (60), and the compressed air in the second intermediate chamber (60) moves into the first intermediate chamber (24). It is possible to move to

The upper end surface of the shaft 68 inserted through the insertion hole 78 of the plate member 42 is inserted into the insertion hole 86 formed in the lower end surface of the piston 58 . A bolt stop hole 88 is formed in the piston 58 from the upper end surface side to the insertion hole 86 , and the connecting bolt 74 stopped at the bolt stop hole 88 is screwed into the bolt hole 76 . . Thereby, the piston 58 and the yoke 64 are connected to each other, and the first to fourth permanent magnets 56a to 56d are indirectly held by the piston 58 via the yoke 64 .

A third sealing member 90 is provided on the side wall of the piston 58 . A space between the piston 58 and the cylinder tube 14 is sealed by the third sealing member 90 . That is, the compressed air in the upper chamber 62 is prevented from leaking into the second intermediate chamber 60 from between the side wall of the piston 58 and the inner wall of the second sliding hole 38 of the cylinder tube 14 . do. For the same reason, the gas in the second intermediate chamber 60 is also prevented from leaking into the upper chamber 62 .

A third wide annular groove 92 is formed in the upper end surface of the piston 58 . A ring-shaped second damper 94 is accommodated in the third annular groove 92 . When the piston 58 reaches top dead center, the second damper 94 abuts against the lower end surface of the entry portion 44 of the head cover 18 (see FIG. 3 ).

The magnet chuck 10 according to the present embodiment is basically configured in the manner described above. Next, its operation and advantageous effect will be described in relation to the operation of the magnet chuck 10 .

The magnet chuck 10 is installed, for example, on a distal end arm of a robot (not shown). Then, as the robot executes a predetermined operation, as shown in FIG. 3 , the workpiece magnetic attachment surfaces of the first to fourth permanent magnets 56a to 56d are opposed to the workpiece 12 . At this time, the piston 58, the yoke 64, and the first to fourth permanent magnets 56a to 56d are located at top dead center, and therefore, at this point, the magnetic force of the first to fourth permanent magnets 56a to 56d is the work piece. (12) is not reached.

Next, compressed air is supplied from the supply/exhaust mechanism to the upper chamber 62 through the second port 50 . The compressed air presses the piston 58 from its upper end surface side. At the same time, under the action of the supply and exhaust mechanism, compressed air is discharged from the lower chamber 23 through the first port 37 . Compressed air in the second intermediate chamber (60) moves to the first intermediate chamber (24) through the communication groove (85), and the compressed air in the first intermediate chamber (24) is connected to the side wall of the flange (66) and the first intermediate chamber (24). 1 It moves to the lower chamber 23 through between the inner wall of the sliding hole 22 and. Then, the above-described compressed air is discharged through the first port (37).

The piston 58 pressurized with compressed air in the upper chamber 62 is displaced (lowered) in a direction approaching the plate member 42 . Since the lower chamber 23, the first intermediate chamber 24, and the second intermediate chamber 60 are under negative pressure, the piston 58 is easily displaced.

Simultaneously with the lowering of the piston 58, the yoke 64 connected to the piston 58 and the first to fourth permanent magnets 56a to 56d held in the yoke 64 descend, as a result, the first to fourth 4 The permanent magnets 56a to 56d approach the work 12 . Finally, the piston 58, the yoke 64, and the first to fourth permanent magnets 56a to 56d reach the bottom dead center, resulting in the state shown in FIG.

When the piston 58 reaches the bottom dead center, it abuts against the first damper 84 provided on the plate member 42 . Since the vibration and collision at the time of abutting are alleviated by the first damper 84, the vibration of the magnet chuck 10 is sufficiently suppressed. Moreover, since damage to the piston 58 and the plate member 42 is avoided, the durability of the magnet chuck 10 can be improved.

When the first to fourth permanent magnets 56a to 56d reach the bottom dead center, each magnetic attachment surface of the work sufficiently approaches with respect to the work 12 , so that the magnetic force is applied to the work 12 . That is, the work 12 is attracted by the magnetic force of the first to fourth permanent magnets 56a to 56d, and is connected to the first to fourth permanent magnets 56a to 56d through the bottom wall portion of the magnet cover 16. aspirated and retained. Since the flange 66 of the yoke 64 functions as a backup yoke, the work 12 is more stably suctioned and held.

Since the magnet cover 16 is made of a paramagnetic metal, the magnet cover 16 cannot function as a yoke. That is, the yoke is not interposed between the first to fourth permanent magnets 56a to 56d and the work 12 . For this reason, influence on the magnetic path formation between the first to fourth permanent magnets 56a to 56d and the work 12 is avoided.

In addition, since the rubber buffer member 28 is installed on the lower end surface of the magnet cover 16, when the work 12 is magnetically attracted to the bottom wall of the magnet cover 16, the magnet cover 16, Furthermore, the stress acting on the magnet chuck 10 is relieved. Accordingly, while the vibration of the magnet chuck 10 can be sufficiently suppressed, damage to the magnet cover 16 or the first to fourth permanent magnets 56a to 56d is avoided.

Here, Figs. 5A and 5B schematically show a region in which magnetic flux and magnetic saturation occur in the prior art having only one N pole on the magnetically attaching surface of the workpiece. In this case, the magnetic flux starting from the N pole constituting the workpiece magnetic attachment surface passes through the inside of the workpiece 12 and goes to the S pole on the back surface thereof. The magnetically saturated region has a substantially cylindrical shape.

On the other hand, FIGS. 6A and 6B are schematic diagrams indicating regions in which magnetic flux and magnetic saturation occur when a pair of N poles and S poles is formed on the magnetically attaching surface of the workpiece. In this configuration, the magnetic flux starting from the N pole constituting the magnetic attachment surface of the workpiece passes through the inside of the workpiece 12 and is directed to the S pole adjacent to the workpiece magnetic attachment surface and the S pole on the back surface. Further, the magnetic flux starting from the N pole located on the back surface of the magnetic attachment surface of the workpiece passes through the inside of the workpiece 12 and is directed to the S pole of the magnetic attachment surface of the workpiece and passes through the inside of the yoke 64, It is directed to the adjacent S pole from the back side of the magnetic attachment surface. Accordingly, magnetic saturation occurs at positions along the diameter along with the cylindrical shape.

Fig. 7 is a schematic diagram showing a region in which magnetic saturation occurs when two pairs of a combination of N poles and S poles are formed on the magnetically attaching surface of a workpiece. In this case, magnetic saturation occurs at positions along two diameters, together with the cylindrical shape. Compared to the above-described configuration, when the combination of the N pole and the S pole is formed, it can be seen that the amount of magnetic flux passing through the work 12 increases.

8 is a magnet chuck (plot of ■ (black square)) using one permanent magnet and having only N poles on the magnetic attachment surface of the workpiece, two permanent magnets, and one N pole and one N pole and A magnet chuck (plot of ◆ (black diamond)) with one pair of N poles and S poles, one S pole, and four permanent magnets of the first to fourth permanent magnets 56a to 56d are used. and the outer diameter and attraction force of the permanent magnet in each of the magnet chuck 10 (plot of ▲ (black triangle)) according to this embodiment in which the combination of the N pole and the S pole on the workpiece magnetic attachment surface is two pairs. It is a graph showing the relationship between Of course, the material and holding force of the permanent magnet in each magnet chuck, and the dimensions of the permanent magnet as a whole are the same.

Also from Fig. 8, it can be seen that the larger the number of magnetic poles on the magnetic attachment surface of the work, the greater the attraction force. In particular, when the total outer diameter of the permanent magnet exceeds 20 mm, or when the thickness of the workpiece 12 becomes smaller, the difference in the attraction force becomes significant. From this, by forming one or more pairs, more preferably two or more pairs of N poles and S poles on the self-adhesive surface of the workpiece, sufficient attractive force is expressed, and the workpiece 12 is made of a thin steel plate and is attracted even if it is a heavy object. It is clear that it can be maintained. This is because, as described above, the amount of magnetic flux passing through the inside of the workpiece 12 increases due to the combination of the N pole and the S pole formed on the magnetic attachment surface of the workpiece.

As described above, by forming the combination of the N pole and the S pole on the magnetic attachment surface of the workpiece, the attraction force to the workpiece 12 is increased. In particular, in this embodiment, since the combination of the N pole and the S pole is formed in two pairs on the work self-adhesive surface, sufficient attractive force is exhibited.

Therefore, according to the present embodiment, if the material and characteristics of the permanent magnets are the same, when the outer diameters are the same, the attraction force to the workpiece 12 can be increased. This means that the work 12 with a larger weight can be sucked and held.

Alternatively, if the attraction force is equal, the entire permanent magnet can be set to a smaller diameter. That is, the magnet chuck 10 can be made compact in size and dimensions.

Thereafter, the robot performs a predetermined operation, so that the tip arm and the magnet chuck 10 are moved to appropriate positions. With this, the work 12 also moves.

Next, under the action of the supply and exhaust mechanism, compressed air is discharged from the upper chamber 62 through the second port 50 . At the same time, compressed air is supplied from the supply/exhaust mechanism to the lower chamber 23 through the first port 37 . A part of this compressed air enters the 1st intermediate chamber 24 from between the flange 66 and the side wall of the 1st sliding hole 22, and also passes through the communication groove 85 and the 2nd intermediate chamber 60 ) to enter. Accordingly, while the flange 66 of the yoke 64 is pressurized by the compressed air in the lower chamber 23 , the piston 58 is pressurized by the compressed air in the first intermediate chamber 24 . The upper chamber 62 is engaged with the negative pressure, so that the piston 58 is displaced (raised) in a direction away from the plate member 42 .

According to this embodiment, the third sealing member 90 is provided on the side wall of the piston 58 . That is, the sealing member is not provided between the yoke 64 and the inner wall of the second intermediate chamber 60 . For this reason, in the above process, the member receiving the pressing force of the compressed air supplied to the upper chamber 62 and the pressing force of the gas moving to the second intermediate chamber 60 is the piston 58 in any case. In addition, although there is a portion covered by the shaft 68 on the lower end face of the piston 58, the flange 66 is also subjected to the pressing force of the compressed air. That is, the pressure-receiving area when the piston 58 is lowered is substantially equal to the pressure-receiving area when the piston 58 is raised. Thereby, it can avoid that the driving force required for raising of the piston 58 falls.

Following the rise of the piston 58, the yoke 64 and the first to fourth permanent magnets 56a to 56d rise integrally. That is, the first to fourth permanent magnets 56a to 56d are physically separated from the work 12 , and as a result, the magnetic force of the first to fourth permanent magnets 56a to 56d does not reach the work 12 . . Accordingly, the work 12 is released from restraint by the magnetic force of the first to fourth permanent magnets 56a to 56d.

The piston 58, the yoke 64, and the first to fourth permanent magnets 56a to 56d finally reach top dead center. That is, it returns to the state shown in FIG.

When the piston 58 reaches top dead center, the disk-shaped projection 80 of the plate member 42 enters the annular recess 72 formed in the flange 66 of the yoke 64 . Further, the second damper 94 provided on the piston 58 abuts against the entry portion 44 of the head cover 18 . Since the vibration and collision at the time of abutting are alleviated by the second damper 94, the vibration of the magnet chuck 10 is sufficiently suppressed. Moreover, since damage to the piston 58 and the head cover 18 is avoided, the durability of the magnet chuck 10 can be improved.

In addition, rotation of the first to fourth permanent magnets 56a to 56d is prevented in the middle of the above process. This is because, as described above, the first to fourth tie rods 54a to 54d are arranged in the vicinity of the first to fourth permanent magnets 56a to 56d. Since the rotation of the first to fourth permanent magnets 56a to 56d is regulated in this way, for example, changes in magnetic flux density in the vicinity of the auto switch are avoided. Accordingly, occurrence of malfunction of the auto switch due to such a change in magnetic flux density can also be avoided.

The first to fourth tie rods 54a to 54d function as members for forming the housing 20 by tightly fixing the head cover 18 , the cylinder tube 14 and the magnet cover 16 together. That is, there is no need to separately use another member to prevent rotation of the first to fourth permanent magnets 56a to 56d. Therefore, while it is possible to avoid an increase in the number of parts, it is possible to achieve compactness of the magnet chuck 10, and it is advantageous in terms of cost.

The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, as shown in FIG. 9, by combining two or more U-shaped permanent magnets 100 (three in FIG. 9), two or more N poles and two or more S poles are formed on the magnetic attachment surface of the workpiece. can be made to exist. In addition to these combinations, it is also possible to combine the U-shaped permanent magnets 100 (two in FIG. 10) so that the magnetic pole surfaces are arranged as shown in FIG. 10 when viewed from the bottom in plan.

Alternatively, as shown in FIG. 11, three or more bar magnets 102 are combined (three in FIG. 11) to form a so-called Halbach arrangement, and a set of N and S poles on the magnetic attachment surface of the workpiece A combination of and may be installed.

In the above embodiment, a plurality of permanent magnets are used, however, one permanent magnet produced by excitation such that two or more pairs of N poles and S poles are present on the magnetic attachment surface of the workpiece can be used.

As an example of such a permanent magnet, as shown in FIG. 12 , magnetization is performed on a predetermined object such as a cylindrical body 98 so that the direction of the magnetic pole is formed in a U-shape. Such a permanent magnet can be produced by bringing a U-shaped magnet close to the bottom surface of the cylindrical body 98, so that an N pole and an S pole are formed on the bottom surface thereof. That is, the bottom surface becomes the work self-adhesive surface, and magnetic poles are not formed on the other bottom surfaces.

Further, by bringing the U-shaped magnet close to one bottom surface of the cylindrical body 98 or the like while bringing the other U-shaped magnet close to the other bottom surface, as shown in FIG. It is possible to manufacture a permanent magnet in which an N pole and an S pole are formed on the bottom surface and an S pole and an N pole are formed on the back surface thereof. That is, in this case, magnetization is made so that the magnetic poles are directed in a direction orthogonal to the workpiece magnetic attachment surface.

Furthermore, the first damper 84 may be installed on the lower end surface of the piston 58 . Meanwhile, the second damper 94 may be installed on the lower end surface of the entry portion 44 of the head cover 18 .

In addition, either the first damper 84 or the second damper 94 may be omitted.

10: magnet chuck
12: Walk
14: cylinder tube
16: magnet cover
18: head cover
20: housing
22: first sliding hole
23: lower chamber
24: first intermediate chamber
37: first port
38: second sliding hole
42: plate member
50: second port
54a to 54d: first to fourth tie rods
56a to 56d: first to fourth permanent magnets
58: piston
60: second intermediate chamber
62: upper chamber
64: York
66: flange
68: axis
78: insertion hole
84: first damper
85: communication groove
94: second damper

Claims (8)

As a magnet chuck (10) for attracting and holding the workpiece (12) with the magnetic force of the permanent magnets (56a to 56d),
A housing including a cylinder tube 14 having a sliding hole 38 through which a piston 58 is displaced, and a head cover 18 attached to the cylinder tube 14 to close one end of the sliding hole 38 . (20) and;
a holding member (66) connected to the piston (58) and holding the permanent magnets (56a to 56d);
a partition member (42) positioned and fixed within the housing (20) to form an inner chamber in the cylinder tube (14) together with the piston (58);
includes,
The magnet chuck 10 further includes at least one of a first damper 84 and a second damper 94 , and the first damper 84 may include any one of the partition member 42 and the piston 58 . It is installed in one to relieve vibration when the piston 58 comes into contact with the partition member 42 , and the second damper 94 is attached to any one of the piston 58 and the head cover 18 . installed to mitigate vibration when the piston 58 comes into contact with the head cover 18,
The combination of the N pole and the S pole is present in one or more pairs on the magnetic attachment surface of the workpiece of the permanent magnets 56a to 56d, and the magnetic attachment surface of the workpiece faces the workpiece 12,
The cylinder tube 14 and the head cover 18 are connected by connecting members 54a to 54d made of ferromagnetic metal, and the connecting members 54a to 54d rotate the permanent magnets 56a to 56d. A magnet chuck (10), which functions as a rotation preventing member to prevent it. The method according to claim 1,
The piston 58 and the holding member 66 are connected through a shaft 68 having a smaller diameter than the piston 58 , and the partition member 42 is connected to the piston 58 and the holding member 66 . ) and is positioned and fixed, and the partition member 42 has an insertion hole 78 into which the shaft 68 is inserted, the magnet chuck 10 . 3. The method according to claim 2,
and the retaining member (66) and the shaft (68) are integrally formed together with the same member (64). The method according to claim 1,
The member comprising the holding member (66) is a yoke (64). delete delete The method according to claim 1,
The connecting members (54a to 54d) are installed at the boundary between the N-pole and the S-pole adjacent to each other on the magnetic attachment surface of the work, the magnet chuck (10). The method according to claim 1,
A sealing member (90) is installed on a sidewall of the piston (58), and a space between the piston (58) and the cylinder tube (14) is sealed by the sealing member (90).

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